1. Field of the Invention
The invention relates to a moldable thermoplastic resin composition.
2. Description of Prior Art
It is known in the art to add a wide variety of compounds to polyamides in order to improve or retain various properties thereof.
More specifically, it is known to manufacture fiber reinforced oriented polyamide films containing additives such as copper salts, alkali metal- or alkaline earth metal halides in order to impart a gloss to the surface of the manufactured product.
For moldable thermoplastic resin compositions it is particularly important to have a material available which has a relatively low viscosity because such a material can be processed easily with high injection speed and short cycle times in injection molding operations. However, compositions having such a low viscosity usually have inherent disadvantages for the properties of the molded articles, such as low molecular weight and low impact strength.
It would be of substantial technical and economical importance to have available for the molding industry a thermoplastic resin composition which can be injected at high speed in the molds in order to attain molded articles with excellent properties such as impact strength, surface gloss and tensile strength at relatively low cost.
The use of resin compositions which are known to be suitable for film manufacturing is not generally feasible for molding processes since a certain minimum viscosity is required to manufacture films in a stable operation whereas for injection molding the viscosity should not be higher than a certain value, as discussed hereinbefore.
Surprisingly, it has now been found that moldable thermoplastic resins with an excellent balance of chemical and physical properties can be obtained by combining a polyamide-containing compound with a relatively small amount of a specific selection of metal salts.